/**
 * Copyright (C) 2002-2015   The FreeCol Team
 * <p>
 * This file is part of FreeCol.
 * <p>
 * FreeCol is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * <p>
 * FreeCol is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.freecol.common.model;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import javax.xml.stream.XMLStreamException;

import net.sf.freecol.common.io.FreeColXMLReader;
import net.sf.freecol.common.io.FreeColXMLWriter;
import net.sf.freecol.common.util.RandomChoice;


/**
 * Represents one of the native nations present in the game.
 */
public class IndianNationType extends NationType
{

    /** Stores the ids of the skills taught by this Nation. */
    private List< RandomChoice< UnitType > > skills = null;

    /** Identifiers for the regions that can be settled by this Nation. */
    private List< String > regions = null;


    /**
     * Create a new native nation type.
     *
     * @param id The object identifier.
     * @param specification The <code>Specification</code> to refer to.
     */
    public IndianNationType( String id, Specification specification )
    {
        super( id, specification );
    }


    /**
     * Is this a European nation type?
     *
     * @return False.
     */
    @Override
    public boolean isEuropean( )
    {
        return false;
    }

    /**
     * Is this a native nation type?
     *
     * @return True.
     */
    @Override
    public boolean isIndian( )
    {
        return true;
    }

    /**
     * Is this a REF nation type?
     *
     * @return False.
     */
    @Override
    public boolean isREF( )
    {
        return false;
    }

    /**
     * Get a message id for the general type of settlements of this nation.
     *
     * @param plural Choose the plural form or not.
     * @return A suitable message id.
     */
    public final String getSettlementTypeKey( boolean plural )
    {
        return getSettlementType( false ).getId( ) + ( ( plural ) ? ".plural" : "" );
    }

    /**
     * Gets the list of regions in which this tribe may settle.
     *
     * @return A list of regions identifiers.
     */
    public List< String > getRegionNames( )
    {
        return ( regions == null ) ? Collections.< String >emptyList( )
                : regions;
    }

    /**
     * Add a region identifier.
     *
     * @param id The object identifier.
     */
    private void addRegion( String id )
    {
        if ( regions == null ) regions = new ArrayList<>( );
        regions.add( id );
    }

    /**
     * Can this Nation can settle the given Tile?
     *
     * @param tile a <code>Tile</code> value
     * @return a <code>boolean</code> value
     */
    /*
    public boolean canSettleTile(Tile tile) {
        if (tile.getType().canSettle()) {
            return canSettleRegion(tile.getRegion());
        } else {
            return false;
        }
    }
    */
    /**
     * Can this Nation can settle the given Region?
     *
     * @param region a <code>Region</code> value
     * @return a <code>boolean</code> value
     */
    /*
    public boolean canSettleRegion(Region region) {
        if (regions.isEmpty()) {
            return true;
        } else if (regions.contains(region.getId())) {
            return true;
        } else if (region.getParent() == null) {
            return false;
        } else {
            return canSettleRegion(region.getParent());
        }
    }
    */

    /**
     * Gets a list of this Nation's skills.
     *
     * @return A list of national skills.
     */
    public List< RandomChoice< UnitType > > getSkills( )
    {
        return ( skills == null )
                ? Collections.< RandomChoice< UnitType > >emptyList( )
                : skills;
    }

    /**
     * Add a skill.
     *
     * @param unitType The <code>UnitType</code> skill taught.
     * @param probability The probability of the skill.
     */
    private void addSkill( UnitType unitType, int probability )
    {
        if ( skills == null ) skills = new ArrayList<>( );
        skills.add( new RandomChoice<>( unitType, probability ) );
    }

    /**
     * Generates choices for skill that could be taught from a settlement on
     * a given Tile.
     *
     * @param tile The <code>Tile</code> where the settlement will be located.
     * @return A random choice set of skills.
     */
    public List< RandomChoice< UnitType > > generateSkillsForTile( Tile tile )
    {
        List< RandomChoice< UnitType > > skills = getSkills( );
        Map< GoodsType, Integer > scale = new HashMap<>( );

        for ( RandomChoice< UnitType > skill : skills )
        {
            scale.put( skill.getObject( ).getExpertProduction( ), 1 );
        }

        for ( Tile t : tile.getSurroundingTiles( 1 ) )
        {
            for ( Entry< GoodsType, Integer > entry : scale.entrySet( ) )
            {
                GoodsType goodsType = entry.getKey( );
                scale.put( goodsType, entry.getValue( )
                        + t.getPotentialProduction( goodsType, null ) );
            }
        }

        List< RandomChoice< UnitType > > scaledSkills = new ArrayList<>( );
        for ( RandomChoice< UnitType > skill : skills )
        {
            UnitType unitType = skill.getObject( );
            int scaleValue = scale.get( unitType.getExpertProduction( ) );
            scaledSkills.add( new RandomChoice<>( unitType,
                                                  skill.getProbability( ) * scaleValue ) );
        }

        return scaledSkills;
    }


    // Serialization

    private static final String PROBABILITY_TAG = "probability";
    private static final String SKILL_TAG = "skill";


    /**
     * {@inheritDoc}
     */
    @Override
    protected void writeChildren( FreeColXMLWriter xw ) throws XMLStreamException
    {
        super.writeChildren( xw );

        for ( RandomChoice< UnitType > choice : getSkills( ) )
        {
            xw.writeStartElement( SKILL_TAG );

            xw.writeAttribute( ID_ATTRIBUTE_TAG, choice.getObject( ) );

            xw.writeAttribute( PROBABILITY_TAG, choice.getProbability( ) );

            xw.writeEndElement( );
        }

        for ( String region : getRegionNames( ) )
        {
            xw.writeStartElement( Region.getXMLElementTagName( ) );

            xw.writeAttribute( ID_ATTRIBUTE_TAG, region );

            xw.writeEndElement( );
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected void readChildren( FreeColXMLReader xr ) throws XMLStreamException
    {
        // Clear containers.
        if ( xr.shouldClearContainers( ) )
        {
            skills = null;
            regions = null;
        }

        final Specification spec = getSpecification( );
        IndianNationType parent = xr.getType( spec, EXTENDS_TAG,
                                              IndianNationType.class, this );
        if ( parent != this )
        {
            if ( parent.skills != null && ! parent.skills.isEmpty( ) )
            {
                if ( skills == null ) skills = new ArrayList<>( );
                skills.addAll( parent.skills );
            }

            if ( parent.regions != null && ! parent.regions.isEmpty( ) )
            {
                if ( regions == null ) regions = new ArrayList<>( );
                regions.addAll( parent.regions );
            }
        }

        super.readChildren( xr );
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected void readChild( FreeColXMLReader xr ) throws XMLStreamException
    {
        final Specification spec = getSpecification( );
        final String tag = xr.getLocalName( );

        if ( SKILL_TAG.equals( tag ) )
        {
            addSkill( xr.getType( spec, ID_ATTRIBUTE_TAG,
                                  UnitType.class, ( UnitType ) null ),
                      xr.getAttribute( PROBABILITY_TAG, 0 ) );
            xr.closeTag( SKILL_TAG );

        }
        else if ( Region.getXMLElementTagName( ).equals( tag ) )
        {
            addRegion( xr.readId( ) );
            xr.closeTag( Region.getXMLElementTagName( ) );

        }
        else
        {
            super.readChild( xr );
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String getXMLTagName( ) { return getXMLElementTagName( ); }

    /**
     * Gets the tag name of the root element representing this object.
     *
     * @return "indian-nation-type".
     */
    public static String getXMLElementTagName( )
    {
        return "indian-nation-type";
    }
}
